Projectile



May 15, 1923. 1,455,354 w. P. PORTER PROJECTILE Fild May 28 1918 INVENTOR We PM? BY M MHPMATTORNEYS Patented May 15, 1923.

UNITED STATES WINFIELD P. PORTER, OF NEW YORK, N. Y.

PROJEC'IILE.

Application filed May 28, 1918. Serial No. 237,021.

To all whom it may concern:

Be it known that I, WINFIELD P. PORTER, of the city of New York, in the county of Bronx and in the State of New York, have invented a certain new and useful Improvement in Projectiles, and do hereby declare that the following is a full, clear, and exact description thereof.

My invention has for an ob ect to prov de a projectile of such character that erosion of the gun from which the pro ectile 1s fired shall be substantially prevented.

Another object of the invention is to bring about the above result in such a manner as to enable projectiles of existing types to be readily equipped to accompllsh 1t.

Another object of the invention 15 to provide such a means for preventing erosion that uniform density of loading of the gun may still be attained.

Further objects and advantages of the invention will be in part obvious, and in part specifically mentioned in the dGSCIlPtIOH Of my invention hereinafter contained, in which I have disclosed certain embodiments of the invention, which, however, are to be considered merely as illustrative of its principle.

In the drawings:

Fig. 1 is a longitudinal section of a portion of a gun containing a projectile equipped 1n accordance with my invention;

Fig. 2 is a detail view showing a somewhat modified form;

Fig. 3 is a view showing the projectile as it leaves the muzzle of the gun;

Fig. 4 is a longitudinal section of a projectile of the fixed ammunition type with my invention applied thereto; and

Fig. 5 is a view similar to Fig. 4 showing a modified form of projectile.

When a projectile is fired having the copper or copper alloy rotating band used in present day practice, it is found that erosion of the gun begins at two points; firstly, at the breech end of the bore, and secondly, at the muzzle of the gun. The action of erosion is of course progressive, increasing in depth and progressing from the breech end of the bore toward the muzzle, and from the muzzle toward the breech so that the rifling of the gun soon wears away to such an extent that it fails to properly rotate the projectile. This action has been explained as follows 2-- When the projectile is rammed home into the throat of the gun, the copper rotating band is not forced at all points into such an intimate engagement with the wall of the gun as to prevent entirely the escape of gases when the explosive charge is fired. Before sufficient pressure has been generated to move the projectile, the gas escapes around the rotating band between the projectile, and throat of the gum-thus wearing away the band and bore so as to make and maintain an annular opening of escape as the projectile begins to move. This action continues until the rotating band has become sufiiciently heated by friction against the bore and by the escaping gases, to expand and completely fill the bore and rifling to prevent further escape of gas past the projectile. Further erosion takes place at the muzzle, since the rotating band is located forwardly of the heel of the projectile so that after said band has moved beyond the muzzle of the gun, an annular space is left for an instant between the heel of the projectile, and the bore of the gun through which space the hot gases of explosion rush at very high velocity.

In an effort to prevent the escape of gases past the projectile during its movement in the gun, various methods and devices have been tried, all of which have apparently failed to attain their object. It has been proposed to supplement the ordinary rotating band with hard fibre discs, or bands, which were intended to fill the throat and rifling more completely during the initial stage of firing of the projectile. Such hard fibre discs or bands, however, have been found ineffective to prevent erosion in the breech end of the bore where the erosion is greatest, and is the determining factor in the period of accuracy of the gun. The bore of the gun almost invaribly contains a certain amount of residue or foreign matter, and its surface is not entirely smooth; the hard fibre has been found not to accommodate itself to such irregularities sufficiently to seal effectively the space between the projectile and the wall of the gun. The gases of explosion tend to move many times faster than the projectile to which they impart motion, and in passing through a small opening, wear away the walls of such opening to a remarkable extent and with great rapidity, so that a small initial leak quickly leads to enlargement of the opening, and to the escape of increas ingly large quantities of gas with consequent increase of erosion.

7 said ring against the wal s of the It is, therefore, of the utmost importance that not even the most minute space be left at any point between the projectile and the bore of the gun, but that continuous and forceful contact be secured at every point in an unbroken circle around the rojectile and between it and the bore of the n, both before and durin the flight of t e projectile through the ore. In order to accompli'sh the above results, I employ a sealing ring (which may be either single or composite) extending around the pro'ectile and located rearw'ardly of a shoul or or enlarged portion thereon, for which shoulder the rear end of the rotating band may conveniently be utilized in projectiles where such rotating band is employed. By the term shoulder is meant an enlarged portion upon the surface of the projectile which the sealing ring may be enga e against to force gun. The sealin ring is composed of a relatively soft material, such as frictioned duck or asbestos,

which consists of duck or asbestos held firmly together by rubber compound. The particular' material employed is not vital, but I consider frictioned duck to be ve advantageous and prefer that it be coated with a lubricant such as graphite, and grease or paraflin. By using a multiple ring composed of a series of two or more rings supporting and $11 plementing each other, the advantages of ifi'erent characteristics, such as elasticity, plasticity, toughness, resistance, and the like may be secured.

In Fig. 1 I have shown an explosion chamber 1 of a gun which has the usual throat 2 leading to the ordinary rifling 3. A projectile 4, having the usual copper rotatin band 5 is shown in the position which it ta es when rammed home. A sealing ring 6 of frictioned duck or similar material having the characteristics above referred to is slipped over the rear end of the shot prior to insertion in the gun; when the projectile is rammed home, the sealing ring 6 will be forced intimately into engagement with the throat 2 of the gun. The projectile may move forwardly to some extent after such engagement has been effected, thus separating the ring 6 from the shoulder formed in the present instance by the rear end of the rotating band 5. The nature of the material of which the ring 6 is composed is such that the space between this ring and the bore of the gun is completely and absolutely sealed, thus preventing entirely the escape of gases past the ring after ignition of the powder charge but before the projectile has begun to move. The pressure of the gases of explosion forces the ring 6 forwardly along the projectile so as to press the said ring intimately into enga ement with the shoulder and thus wedges t e material even more firmly against the bore of the gun. This presure continues while the projectile travels through the chase so as to seal the gases against escape during the entire period of travel of the rojectile through the gun. The material of the ring 6 is of such character as to fill completely the space between the projectile and the bore of the gun, even though the surface of said bore be irregular, since it possesses sufficient elasticity to accommodate itself to any irregularities in the wall of the gun.

As the projectile passes'through the rifling, the ring 5 of course will be pressed into requisite sha e and with proper dimensions, such ban may take the form shown in Fig. 3 in which it hasa rearwardly extending lip 6 which will seal the muzzle of the gun against escape of gases after the copper band 5 has passedtherc beyond. In this way, erosion may be substantially prevented at both vital points in the bore of .the gun.

It will also be noted that my invention may be merely in the nature of an addition to projectiles of standard forms, since the advantages of the invention may be obtained by placing a ring upon projectiles of the existing types.

If desired, I may employ a composite sealing ring consisting of the soft ring 6 and a further ring 7, which, in the present instance, is shown (Fig. 2) between the rin 6 and the shoulder formed by the rear end of band 5. The ring 7 may be formed of a harder tougher material, such as hard fibre, thus securing the advantages of softness and elasticity, toughness and resistance in the sealing ring.

As shown in Fig. 2-, a packing ring 8 may be employed to keep the forward edge of the sealing ring in shape and to prevent the material thereof from being forced to too great an extent between the rotating band 5 and the wall of the gun, such packing ring being preferably of soft metal such as copper, and acting somewhat like a piston ring. It may be supported in any suitable manner as by a shoulder on the sealing ring, as shown.

If desired, a sleeve 9 of comparatively soft metal, such as cop r, may be placed over the heel of the pro ectile to receive the sealing ring and any associated parts. This band 9 may alsoperform the function of engaging closely the rifling at the muzzle of the gun so as to seal the muzzle effectively after the rotating band 5 has passed beyond the same. A raised portion 10 may be provided upon the sleeve 9 to insure. close engagement between such sleeve and the bore of the gun. In some instances, it may also be desirable to employ a stop to prevent the sealing ring from being pulled from off the projectile before or during the loading of the gun; in cases where the raised portion 10 is used, such raised portion forms a suitable stop without the necessity of usin an additional element for this purpose. t will be noted that in the use of my invention each shell may be rammed home to identically the same position, since the sealing ring yields or moves rearwardly (relatively speaking), until the rotating band 5 is seated against the ends of the rifling 3, thus permitting uniform density of loading.

As shown in Fig. 4, my invention ma be readily applied to projectiles of the xed ammunition type, as by placing a sealing ring 11 between the rear end of shot 12 and the cartridge case 13, in which relation it will perform the same functions as above described in connection with Figs. 1 to 3. This figure also illustrates the use of a projectile having a tapered rear end 12 to receive the sealing ring, so that the ring is forced even more closely into engagement with the bore of the gun, as it moves forwardly with respect to the projectile. As illustrated in Fig. 5, supplementary sealing ring 14, or packing ring 15, may also be used in connection with projectiles of the fixed ammunition type which members act in the same way as parts 7 and 8 previously described.

While I have described certain specific forms of my invention, it is obvious that many of the details may be changed without departing from its principle.

I claim:

1. A projectile having the usual rotatin band surrounding the same, a sealing ring 0% relatively soft material surrounding the body of said projectile and disposed rearwardly of said rotating band, said sealing ring being movable along the body of the pro ectile into engagement with or away from said rotating-band. A

2. A projectile having the usual rotating band surrounding the same, a sealing rin of relatively soft elastic material surrounding the body of said projectile and disposed rearwardly of said rotating band, said sealing rin being movable along the body of the pro ectile into engagement with or away from said rotating band.

3. A projectile having an annular shoulder thereon, a sealing ring of relatively soft material surrounding said projectile, said ring being dispose rearwardly of said shoulder, and a soft metal packing ring disposed adjacent saidshoulder.

4. A projectile having an annular shoulder thereon, a sleeve of soft metal disposed rearwardl of said shoulder, and a sealing rin of re atively soft material surrounding sai sleeve.

5. A projectile having an annular shoulder thereon, a sleeve of soft metal disposed rearwardly of said shoulder, and a sealing rin of relatively softmaterial surrounding sai sleeve, said ring being movable along the projectile, into engagement with or away from said shoulder.

6. A projectile having the usual rotating band surrounding the same, a sealing ring of relatively compressible material surrounding the body of said projectile and disposed rearwardly of said rotating band, said sealing ring being movable along the body of the projectile into engagement with or away from said rotating band.

'7. A projectile having an annular shoulder thereon, a sleeve of soft metal on the rear end of the projectile, and a ring of relatively soft material located rearwardly of said shoulder, said sleeve having a raised portion, adapted to engage closely the rifiing and muzzle of the gun and forming a stop for said ring.

8. A projectile having an annular shoulder thereon, a. sleeve of soft metal on the rear end of the projectile, said sleeve having a portion adapted to engage closely the rifiing and muzzle of the gun, and a sealing ring of relatively soft material located rearwardl of said shoulder.

9. g projectile having an annular shoulder thereon, a sleeve of soft metal on the rear end of the pro'eotile, said sleeve having a portion adapted to engage closely the rifling and muzzle of the gun, a sealing ring of relatively soft material located rearwardly of said shoulder, and said ring being movable along the projectile toward and from said shoulder.

In testimony that I claim the foregoing I have hereunto set my hand.

WINFIELD P. PORTER. 

